1. Field of the Invention
The present invention relates to oil mist separators for an internal combustion engine, and more particularly to the oil mist separators of a type that separates oil mist from blow-by gas produced in the internal combustion engine.
2. Description of the Related Art
In current days, for protecting the environment from pollution, internal combustion engines for motor vehicles are usually provided with a blow-by gas processing system through which the blow-by gas leaking from the combustion chambers to the crankcase is led into an intake system of the engine for burning unburnt components of the blow-by gas. Since the blow-by gas passing through the crankcase contains oil mist that would lower the performance of the intake system, an oil mist separator is usually provided in for example a cylinder head cover for separating and removing the oil mist from the blow-by gas.
Some of such oil mist separators are disclosed in Japanese Laid-open Patent Application (tokkai) 2009-121281 and Published International Patent Application 2013/179829. The oil mist separator disclosed in the former generally comprises a separator chamber, a partition wall installed in the separator chamber, a plurality of openings formed in the partition wall and an impinge wall installed in the separator chamber at a position downstream of the partition wall. In operation of the engine, the blow-by gas is forced to pass through the openings. With this passing, the blow-by gas is highly accelerated before impinging against the impinge wall, and thus the oil mist in the blow-by gas is suitably separated and removed. The other oil mist separator disclosed in the latter is substantially the same as that of the former except that in the latter, the impinge wall is lined or covered with a fiber laminate for improving the oil mist separation and removing.